Claude Guéant, then Interior Minister of France, waiting with police officers as security forces lay siege to the apartment block where Mohamed Merah, the man suspected of a series of deadly shootings, was holed up on March 22, 2012 in Toulouse, France

Coming as it did just weeks before a tight French presidential election last spring, the killing spree by self-described al-Qaeda militant Mohammed Merah mixed presidential politics with growing concerns about public security in France. Both of those elements have only taken on additional significance during the eight months since Merah was killed in a gun battle with police March 22; recent events have sharpened suspicions that intelligence officials and government authorities may have erred in dealing with the jihadi who murdered seven people.

The latest revelation in the debate over Merah’s handling came Nov. 1. During an interview with Europe 1 radio, Claude Guéant — a close adviser of former President Nicolas Sarkozy, and Interior Minister at the time of Merah’s spree — staunchly defended the actions of the government and intelligence officials in the case. But Guéant also acknowledged a previously unknown failure during the police siege of the jihadi’s Toulouse apartment.

“There was a lapse during the intervention when Merah left his apartment to make a telephone call, eluding — apparently by passing through the basement of the building he knew well, having lived in it — police surveillance,” Guéant said. “Apart from that, the services kept Merah under watch.”

That’s a pretty huge “apart.” Meanwhile, it’s still unknown who Merah went to call, or why the 23-year-old extremist returned to his apartment if he knew it was surrounded by elite police forces preparing to take him dead or alive. As a result, Guéant’s revelation of additional detail only adds more questions to a growing list of unknowns about the Merah case. It also further stokes the claims of those contending an intelligence failure allowed the jihadi to freely prepare and execute his attacks.

Such suspicions may be behind promises made Nov. 1 by current President François Hollande that “all light will be [cast] on what happened,” and “all lessons learned” from the way security forces oversaw the Merah case. Hollande made that pledge standing next to Israeli Prime Minister Benjamin Netanyahu during a memorial ceremony for four Jewish victims murdered by Merah on March 19 outside the Ozar Hatorah school in Toulouse.

Hollande isn’t alone in wanting to clear up gray areas. On Nov. 2, ecologist legislator Noël Mamère called for a parliamentary commission to be formed by officials across the political spectrum to investigate Merah’s handling by security forces. The previous week, police inspectors unveiled their independent audit of how Merah was supervised since he first came to the attention of intelligence services in 2006. The report cited “objective failures” in the surveillance and analyses of Merah as a threat.

Both that report and earlier media leaks of French intelligence documents painted a picture of France’s main domestic spy agency failing to appreciate Merah’s contacts and trips abroad — including two visits to Pakistan — as strong evidence of his tightening embrace of extremism. They were also faulted for having been duped by Merah’s decidedly impious nightlife activities, and similarly interpreting descriptions of his trips to Pakistan as tourism, as he sought to mask his radicalization and deadly projects.

More recently, French newspapers have published leaks from a judicial investigation stemming from civil suits filed by families of Merah’s victims claiming authorities fell down on the job. Those media reports cite testimony by regional intelligence officials in Toulouse stressing they repeatedly alerted superiors at the national level to their views that Merah was a growing threat to public safety. Those warnings, the reports show regional officials as saying, were discounted or ignored by bosses in Paris.

Those leaks also quote the Toulouse intelligence officials recalling senior analysts in Paris not only disagreeing with local views that Merah was evolving into a potential threat but also ordering surveillance of him reduced in early 2012 — just weeks before he began his killing spree. Those regional officials say that decision was taken amid discussions by Paris brass about recruiting Merah as an informant. Perhaps unsurprisingly, the investigation leaks also describe those same Toulouse functionaries as saying their services quickly suspected a jihadist perpetrator — with Merah listed among six leading radical suspects — when the first shooting victims were killed in March 2012. That Islamist line was discounted by officials in Paris who were initially convinced it was instead an extreme-right attacker — right up until three children and an adult were gunned outside Ozar Hatorah.

Both Guéant and the former head of France’s domestic intelligence agency have been adamant that no serious errors were made, nor potential dangers discounted in handling Merah either before or after he went into attack mode. They say any faulty decisions made were a direct result of Merah’s remarkable talents of misdirection in hiding his extremist hand and masking his true intentions. At worst, they say, a human mistake of underestimating Merah’s extremism — not an outright intelligence failure — underlay the tragedy.

Some members of France’s antiterrorism forces believe that’s probably true but say a degree of political manipulation was also involved. Those officials have told TIME a major failing in the Merah case — corroborated in the police audit and leaked investigation testimony — was the repeated refusal of intelligence officials in Paris to grant requests from Toulouse agents to “judicialize” the case. Under France’s multidisciplinary antiterrorism structure, that process involves intelligence and police units to be joined by specialized investigative magistrates launching legal inquiries into suspected radical activities. Adding that judicial dimension greatly expands the legal limits of electronic surveillance and physical searches allowed, and permits judges to participate in the collection of evidence that will eventually be taken to court.

So if that step is standard procedure under France’s counterterrorism structure, why was it never taken with Merah?

Some insiders in that wider system say that hardening aversion to “judicialize” terrorism cases reflected Sarkozy’s own disdain of investigating magistrates — a function Sarkozy tried and failed to reform into extinction to allow politically appointed public prosecutors assume the lead role in inquiries. Yet with Sarkozy loyalists heading France’s main domestic intelligence and police units, security officials say the then President’s preference to let spooks and cops deal with security threats by themselves was easy to arrange: those agencies simply declined to hand inquiries to specialized judicial authorities unless they were forced to by events.

“Once Sarkozy failed to eliminate independent investigating magistrates, the decision was made at some level to just stop transmitting politically potent terror cases to judges unless it couldn’t be legally avoided,” one senior counterterrorism official recently told TIME. “This was clearly the case with Merah. But one problem in keeping those cases close to the center of power in Paris is you lose the experience and divergent insight you have when all the usual players in antiterrorism are involved — perspective and debate is considerably narrowed. The other problem is if something goes wrong, as it did with Merah, blame gets focused back on that center of power.”

That’s what’s happening now, even though it remains from certain any proof of serious, culpable intelligence failure will be established in the Merah case. It’s also unclear whether the ongoing finger-pointing will wind up inflicting lasting political damage to the reputation of Sarkozy and other conservative leaders of that time. But one consequence of the Merah case is already clear, the French antiterrorism official confides.

“Before Merah — and Sarkozy’s presidential defeat — virtually nothing was ‘judicialized’ unless there was no choice,” he says. “Now, everything is ‘judicialized’ as soon as there’s basis for it.”